The present invention relates generally to display devices, and more particularly to a light modulating display device wherein an electrokinetically mobile, light pervious liquid is moved into and out of capillary openings under the influence of an electric field to cause variations in surface concavity of the liquid in the openings to modulate the light passing therethrough.
U.S. Pat. Nos. 4,010,321 and 4,030,813 assigned to the same assignee as the present invention disclose light modulating devices which comprise a layer of electroosmotically movable liquid of which the thickness is locally controlled in response to local loop currents produced by an electrostatic charge pattern. The charge pattern may be produced by a plurality of intersecting electrodes immersed in the liquid or by an accelerated intensity-modulated cathode ray beam scanned across the liquid layer. Light incident on the device is refracted by local gradients and projected onto a screen through the grille of a Schlieren lens system.
However, the use of a Schlieren lens system adds to the cost of the light modulating device and is not desirable for a wide range of applications. Further, the image contrast of the prior art light modulating device is still not satisfactory for practical applications.